1. Field of the Invention
The present invention relates to a joint assembly comprising a first shaft, a casing having two openings at its axial ends, receiving an end portion of the first shaft through the opening at one end and provided with a flange on the periphery of the other end, a second shaft provided at its one end with a flange to be joined to the flange of the casing, and a sealing means provided between the flanges.
2. Description of the Prior Art
In a sealing device for a joint assembly of so-called flange coupling type, such as a tripode joint assembly, an end cover is placed as a blind plate between the flanges so that the periphery of the end cover is held between the flanges and a sealing member made of rubber is held between a portion of the end cover inside of the periphery and the flange of the casing, whereby the opening of the casing is sealed.
In order to provide the above mentioned function, the end cover is formed by pressing to have a setting portion for the sealing member inside of said periphery, which setting portion is recessed from said periphery. Consequently, the back side of the setting portion is protruded toward the flange of the second shaft.
In a tripode joint assembly to be mounted on a drive shaft assembly for an automobile, the outer diameters of the flanges are desired to be as small as possible because of the limited space for the installation. Accordingly, in order to accomodate the protruded configuration of the above mentioned setting portion of the end cover and to minimize the outer diameter of the flange, it was necessary to provide a stepped or recessed portion on the flange of the second shaft, thereby to receive the protruded setting portion of the end cover. However, in the tripode joint assembly, the contour of the casing, especially the contour of the casing formed by pressing a cylindrical member, is a generally triangular shape with rounded corner portions, and correspondingly, the setting portion of the end cover is similarly shaped. It is rather difficult to form a stepped portion having a correspondingly generally triangular shape, on the flange of the second shaft, and a special machine is required for such machining, involving great installation costs for the machine. Yet, a great deal of work will be involved in such machining.